Possible bug: SCNTechnique handleBindingOfSymbol. renderedNode is nil

The SceneKit SCNTechnique will call-back a block allowing an app to supply custom data to an OpenGL Shader.

for example

     technique.handleBindingOfSymbol("prevMvp"){
                        programID, location, renderedNode, renderer in
                        print("nodeName \(renderedNode.name)")
                        let m = renderedNode.transform
                        ...

The block must conform to.

public typealias SCNBindingBlock = (UInt32, UInt32, SCNNode, SCNRenderer) -> Void

But my block is being called with renderedNode pointing at 0x00000

This is not an optional. It should not be zero.
The node reference is invalid. The SCNRenderer (and the other parameters) are correct.